The present invention relates to new 27-halo derivatives of the compounds collectively defined as LL-F28249. These LL-F28249 antibiotics preferably are produced by the fermentation of the microorganism Streptomyces cyaneogriseus subspecies noncyanogenus deposited in the NRRL under deposit accession No. 15773. The morphological characteristics, compounds and method for their production are disclosed in European Patent Application No. 170,006, incorporated herein by reference thereto.
The LL-F28249 components are complex macrolids which have 5 olefinic bonds. The selective halogenation, preferably bromination or chlorination, at the C.sub.27 of the C(26,27) double bond is the subject matter of the present patent application. These halogen derivatives have a high degree of anthelmintic, ectoparasitic, insecticidal, acaricidal and nematicidal activity and, therefore, are useful in the prevention, control or treatment of infections or infestations in warm-blooded animals and agricultural crops.
Further, the present compounds also are useful intermediates for the preparation of other novel antiparasitic, insecticidal and nematicidal compounds.